Performance Assessment of a Novel Multianalyte Methodology for Celiac Disease Biomarker Detection and Evaluation of the Serology-Alone Criteria for Biopsy-Free Diagnosis.

CONTEXT.­: Serology plays a vital role in celiac disease (CD) diagnosis, and the latest European guidelines advocate for biopsy-free diagnoses in patients with ≥10× the upper limit of normal (ULN) of anti-tissue transglutaminase (tTG) immunoglobulin A (IgA) antibodies. OBJECTIVE.­: To assess performance characteristics of a novel automated particle-based multianalyte technology (Aptiva) for anti-tTG and anti-deamidated gliadin peptide (DGP) antibody detection as compared to the traditional enzyme-linked immunosorbent assay (QUANTA Lite). Performance characteristics of the ≥10× ULN anti-tTG IgA criteria for serologic diagnosis of CD were also evaluated. DESIGN.­: Sera samples from 703 patients were tested for anti-tTG IgA, anti-tTG immunoglobulin G (IgG), anti-DGP IgA, and anti-DGP IgG antibodies on both platforms. In total, 127 patients had medical information and were classified as CD-positive (n = 58) and CD-negative (n = 69) based on biopsy results. Clinical performance characteristics were evaluated. RESULTS.­: Anti-tTG IgA detection showed equal clinical sensitivity and specificity of 91% sensitivity and 99% specificity on both platforms. Anti-tTG IgG resulted in moderate sensitivity of 69% and 72%, but high specificity of 100% and 94% on Aptiva and QUANTA Lite, respectively. Anti-DGP IgG displayed comparable sensitivity of 90% and 81%, and a specificity of 94% and 99%, on Aptiva and QUANTA Lite, respectively. Anti-DGP IgA demonstrated greater sensitivity on QUANTA Lite (83%) than Aptiva (69%) and similar specificities of 97% and 98% on QUANTA Lite and Aptiva, respectively. At ≥10× ULN levels for anti-tTG IgA, Aptiva displayed a sensitivity of 72% and a specificity of 100%, and QUANTA Lite showed a sensitivity of 69% and a specificity of 100%. CONCLUSIONS.­: Aptiva is a reliable method to measure CD biomarkers with reduced hands-on necessity and high-throughput capabilities. This study supports the use of a ≥10× ULN anti-tTG IgA biopsy-free approach for serologic diagnosis of CD.

Protein Immunization Induces Memory CD4+ T Cells That Lack Th Lineage Commitment.

Acute viral infection generates lineage-committed Th1 and T follicular helper (Tfh) memory cells that recall their lineage-specific functions following secondary challenge with virus. However, the lineage commitment of effector and memory Th cells in vivo following protein vaccination is poorly understood. In this study, we analyzed effector and memory CD4+ T cell differentiation in mice (Mus musculus) following adjuvanted glycoprotein immunization compared with acute lymphocytic choriomeningitis virus infection. Glycoprotein immunization induced CXCR5- non-Tfh effector and memory CD4+ T cells that surprisingly had not undergone polarization toward any particular Th cell lineage but had undergone memory differentiation. However, upon challenge with virus, these Th lineage-nonpolarized memory CD4+ T cells were able to generate Th1 secondary effector cells, demonstrating their lineage plasticity. In addition, Tfh and memory Tfh cells were generated in response to protein immunization, and these cells differed from infection-induced Tfh cells by their lack of the transcription factor Tbet. Rechallenge experiments demonstrated that viral infection, but not protein immunization, during either the primary or secondary immune response, restricts the recall of Bcl6 expression and the generation of germinal center Tfh cells. Together, these data demonstrate that protein immunization generates a combination of nonpolarized memory cells that are highly plastic and memory Tfh cells that can undergo further Th1-like modulation during a secondary response to viral infection.